[TheForge] How to melt steel with sunlight: 2

[peter fels & phoebe palmer]

Assuming we are talking about a forge here, the precise focus hardly 
matters and Jerry's sat dish lined with aluminum foil might well do it.
But a big suspended lens would be less components  to build. Once all 
that heat is gathered, it  becomes trickier to direct and manipulate.
The reflector would be pointed the wrong way so you'd need shaped, heat 
tolerant mirrors.

On 11/29/2010 6:39 PM, Bruce Freeman wrote:
> Take a big cylinder or bowl - like 6' dia, fill it with liquid and
> spin it at a low speed the resulting surface will be a parabola of
> rotation -- i.e., a parabolic mirror shape.  If you can get it to
> freeze without significant contraction or expansion, you're most of
> the way there to a parabolic mirror.  Or use a reflective liquid
> (mercury comes to mind, but is too dense, expensive, and toxic to be
> reasonable) and just keep spinning it !
>
> On Mon, Nov 29, 2010 at 2:11 AM, peter fels&  phoebe palmer
> <artgawk at thegrid.net>  wrote:
>> Why polish up there Jerry. when you can just use it as a mold to cast an
>> ice lens, or 7?
>>
>> On 11/28/2010 9:02 PM, Jerry Frost wrote:
>>> I've given thought to buying an old 6' plus satellite dish and polishing it
>>> but wouldn't you know by time I had room they were pretty much all gone. Oh
>>> well.
>>>
>>> Jer
>>> ----- Original Message -----
>>> From: "peter fels&    phoebe palmer"<artgawk at thegrid.net>
>>> To: "Blacksmithing List Sponsored by ABANA"<theforge at mailman.qth.net>
>>> Sent: Friday, November 26, 2010 11:30 PM
>>> Subject: Re: [TheForge] How to melt steel with sunlight: 2
>>>
>>>
>>>> I brought the solar forge up because historically, vast forests, all
>>>> across the old world,  were felled to make charcoal
>>>> for metal smelting and working.
>>>> It was an ecological disaster.
>>>> OK..the potters helped..but we made the axes.
>>>>
>>>> On 11/26/2010 2:42 PM, Bruce Freeman wrote:
>>>>> How to melt steel with sunlight:
>>>>>
>>>>> http://blog.makezine.com/archive/2010/11/2_square_meters_of_sunlight_focused.html
>>>>>
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>
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